#!/usr/bin/env node

const {Readable} = require('stream');
//  ==
//const Read = require('stream').Readable;

const rs = new Readable();
let c = 'a'.charCodeAt(0);

rs._read=()=>{
  rs.push(String.fromCharCode(c++));
  if(c==='z'.charCodeAt(0)+1) 
    rs.push(null);
}

rs.pipe(process.stdout);
